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Descriptions

W.D. Clayton, M. Vorontsova, K.T. Harman & H. Williamson

© Copyright The Board of Trustees, Royal Botanic Gardens, Kew.

Cymbopogon citratus

HABIT Perennial; caespitose. Rhizomes short. Culms 100–200 cm long. Ligule an eciliate membrane. Leaf-blades tapering towards sheath; 45–90 cm long; 10–20 mm wide; aromatic.

INFLORESCENCE Synflorescence compound; paniculate; 30–60 cm long; open. Inflorescence composed of racemes; terminal and axillary; subtended by a spatheole; enclosed.

Racemes 2; paired; deflexed; 1–2.5 cm long. Rhachis fragile at the nodes; semiterete; villous on margins. Rhachis hairs 2–3 mm long. Rhachis internodes linear. Rhachis internode tip transverse; cupuliform. Raceme-bases flattened; subequal.

Spikelets in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels linear; semiterete; villous; with 2–3 mm long hairs.

STERILE SPIKELETS Basal sterile spikelets well-developed; 2 in number (lower raceme); 0 in upper raceme; sessile and pedicelled. Basal sterile spikelet pedicels free; linear. Basal sterile spikelets equalling fertile.

Companion sterile spikelets well-developed; male; elliptic; 4–4.5 mm long; shorter than fertile; deciduous with the fertile. Companion sterile spikelet glumes chartaceous; acute; muticous. Companion sterile spikelet lemmas 2; enclosed by glumes.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets linear, or lanceolate; dorsally compressed; 5–6 mm long; 0.7 mm wide; falling entire; deciduous with accessory branch structures. Spikelet callus pilose; base obtuse; inserted.

GLUMES Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume lanceolate; 1 length of spikelet; 2-keeled; keeled laterally; wingless. Lower glume intercarinal veins absent. Lower glume surface flat, or concave. Lower glume apex emarginate. Upper glume lanceolate; 1-keeled. Upper glume apex acute.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret hyaline. Fertile lemma lanceolate; hyaline; without keel. Lemma apex entire, or dentate; 2 -fid; muticous, or mucronate. Palea absent or minute.

FLOWER Anthers 3.

DISTRIBUTION Africa: north, Macaronesia, west tropical, west-central tropical, east tropical, southern tropical, middle Atlantic ocean, and western Indian ocean. Asia-temperate: China and eastern Asia. Asia-tropical: India, Indo-China, Malesia, and Papuasia. Australasia: Australia. Pacific: southwestern, south-central, northwestern, and north-central. North America: Mexico. South America: Mesoamericana, Caribbean, northern South America, western South America, Brazil, and southern South America.

NOTES Andropogoneae. FTEA.

Please cite this publication as detailed in How to Cite Version: 27th January 2014.